So, if "the alleged suspect" is entitled to rights of fair trial, appeals, yadda yadda, would a CCW holder taking him out on the spot be violating his rights to those things, and therefore be wrong? I mean, it's confusing. Seems like it would have been OK for someone to cap him on the spot in the act, but not after they catch him afterwards still armed and blood-spattered?

From what I've heard, he'd taken a shitload of Vicodin beforehand and was probably too loaded to shoot himself. That's probably why they caught him, he was too fucked up to decide whether to leave or not.